The trio, named as Herwig F., Ina F. and Thomas R. “are strongly suspected of having worked for a Chinese secret service” at some point before June 2022, the prosecutors said in a statement.

The suspects were arrested in Duesseldorf and Bad Homburg in western Germany and their homes and workplaces were also searched.

Thomas R. is suspected of working as an agent for an employee of the Chinese Ministry of State Security (MSS), obtaining information in Germany on technologies that could be used for military purposes.

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He is said to have established contact with Herwig F. and his wife Ina F., who run a company in Duesseldorf, in order to access such technologies and make contacts in the German scientific and research community.

The company signed an agreement with a German university to provide “knowledge transfer”, the prosecutors said.

The first phase of the project was to prepare a study for a Chinese “contractual partner” on state-of-the-art machine parts used in powerful ship engines, they said.

The contractual partner was the MSS employee that Thomas R. was working for and the project was financed by Chinese state agencies, they said.

At the time of their arrest, the suspects were also allegedly in further negotiations about research projects that could be useful for the expansion of China’s maritime combat capabilities.

The trio is also accused of purchasing a special laser from Germany on behalf of the MSS and exporting it to China without authorisation.